Latex polymer for improved paint washability

ABSTRACT

The present invention is directed to a coating composition or paint comprising a polymer system including one or more latex polymers, wherein the acid content and molecular weight of the latex polymers are balanced to provide a coating composition that demonstrates optimal performance characteristics of washability or stain resistance, especially when used in a flat finish paint.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of International Application SerialNo. PCT/US13/028863, filed on Mar. 4, 2013 and entitled “Latex Polymerfor Improved Paint Washability”, which claims the benefit of U.S.Provisional Application Ser. No. 61/607,087 filed Mar. 6, 2012 andentitled “Latex Polymer for Improved Paint Washability”. Each of theaforementioned applications are incorporated herein by reference in itsentirety.

BACKGROUND

For environmental and regulatory reasons, latex compositions, because oftheir lower toxicity and lower volatile organic compound (VOC) content,are now preferred for painting architectural surfaces, and especiallyinterior surfaces. However, latex paint compositions, especially flatpaint compositions, have poor stain resistance and are not typicallywashable, and therefore, use of such paints is generally limited toceilings or low traffic areas of a building or home.

From the foregoing, it will be appreciated that there is a need forlatex compositions for use in paint compositions, including flat finishcompositions that demonstrate excellent performance characteristics,including washability or stain resistance.

SUMMARY

The present invention provides coating compositions that include latexpolymers for use in low VOC paint, including flat finish paint, forexample. Surprisingly, and in contravention of industry bias, paintsthat include the polymer compositions described herein are capable ofbeing washed or cleaned without significant film or paint loss.

Accordingly, in one embodiment, the present invention provides paint orcoating compositions that include a polymer system with at least 10% to30% of the system having a molecular weight of about 10,000 to 40,000and acid percent of about 5 to 10. Such a coating composition, when usedin a flat finish paint, for example, has washability rating of at least7. In another embodiment, the present invention provides a method ofmaking a paint or coating composition by providing one or more latexpolymers, and adjusting the acid content and molecular weight of thelatex polymers to obtain a polymer system with at least 10% to 30% ofthe system having a molecular weight of about 10,000 to 40,000 and acidpercent of about 5 to 10. Coating compositions, especially flat finishpaints, for example, made by this method have washability rating of atleast 7.

The above summary of the present invention is not intended to describeeach disclosed embodiment or every implementation of the presentinvention. The description that follows more particularly exemplifiesillustrative embodiments. In several places throughout the application,guidance is provided through lists of examples, which examples can beused in various combinations. In each instance, the recited list servesonly as a representative group and should not be interpreted as anexclusive list.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

Selected Definitions

Unless otherwise specified, the following terms as used herein have themeanings provided below.

The term “component” refers to any compound that includes a particularfeature or structure. Examples of components include compounds,monomers, oligomers, polymers, and organic groups contained there.

The term “double bond” is non-limiting and refers to any type of doublebond between any suitable atoms (e.g., C, O, N, etc.). The term“ethylenically unsaturated” refers to compounds that include acarbon-carbon double bond (i.e., —C═C—).

As used herein, the term “washability” refers to the relative ease ofremoving dirt, soil, discolorations, and the like, from the a dried filmof a coating applied to a substrate surface, typically an interiorarchitectural surface such as a wall, for example. The soil or dirt istypically removed by washing with abrasive and/or non-abrasive cleaningcompositions. To measure washability, a standard test method, ASTMD3450-00 (Standard Test Method for Washability Properties of InteriorArchitectural Coatings) is used. The terms “washability” and “stainresistance” are used interchangeably herein.

Unless otherwise indicated, a reference to a “(meth)acrylate” compound(where “meth” is bracketed) is meant to include both acrylate andmethacrylate compounds.

The term “on”, when used in the context of a coating applied on asurface or substrate, includes both coatings applied directly orindirectly to the surface or substrate. Thus, for example, a coatingapplied to a primer layer overlying a substrate constitutes a coatingapplied on the substrate.

Unless otherwise indicated, the term “polymer” includes bothhomopolymers and copolymers (i.e., polymers of two or more differentmonomers).

The term “comprises” and variations thereof do not have a limitingmeaning where these terms appear in the description and claims.

The terms “preferred” and “preferably” refer to embodiments of theinvention that may afford certain benefits, under certain circumstances.However, other embodiments may also be preferred, under the same orother circumstances. Furthermore, the recitation of one or morepreferred embodiments does not imply that other embodiments are notuseful, and is not intended to exclude other embodiments from the scopeof the invention.

As used herein, “a”, “an”, “the”, “at least one” and “one or more” areused interchangeably. Thus, for example, a coating composition thatcomprises “an” additive can be interpreted to mean that the coatingcomposition includes “one or more” additives.

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, 5, etc.). Furthermore, disclosure of a range includesdisclosure of all subranges included within the broader range (e.g., 1to 5 discloses 1 to 4, 1.5 to 4.5, 1 to 2, etc.).

DETAILED DESCRIPTION

Embodiments of the invention described herein feature coatingcompositions that include a polymer system, used as the binder componentor as a blending ingredient in a paint, for example, with at least 10%to 30% of the system having a molecular weight of about 10,000 to 40,000and acid percent of about 5 to 10. Such a coating composition, when usedin a flat finish paint, has washability rating of at least 7. Thecomposition as described herein is preferably substantially free ofvolatile organic compounds (VOC), and is used to make paints, includingflat finish paints, for example, for interior architectural surfaces.Preferred paints demonstrate excellent performance characteristics, suchas superior stain resistance or washability, for example.

In an embodiment, the polymer system described herein is suitable foruse in a low-VOC or zero-VOC paint to be used as an interiorarchitectural coating or wall paint, for example, especially a paintwith a flat finish.

The term “finish,” as used herein, refers to the texture or appearanceof a paint when applied and dried on to a substrate, typically anarchitectural surface such as an interior wall, for example. The termmay also be used to refer to the paint used to produce said texture orappearance when applied to an architectural surface such as an interiorwall. Paints are typically found in a variety of finishes such as, forexample, flat or matte, eggshell, satin, semigloss and glossy finishes.

The finish of a particular paint is a function of the pigment-to-binder(P-to-B) ratio of the paint or composition, where the higher the P-to-Bratio, the less reflective the paint. For example, a flat paint has ahigh P-to-B ratio and dries to a non-reflective or minimally reflectiveappearance when applied to an architectural surface. The P-to-B ratio issometimes expressed as a pigment volume concentration (PVC), i.e., thevolume fraction of pigment in the total volume of dried solid paint.Architectural paints, including flat paints, for example, can be madewith a wide range of PVC. For example, the paint described hereinpreferably has PVC of about 25 to 60, more preferably 30 to 55. Becauseof the relatively high amount of pigment, i.e., PVC of about 40 to 55, aflat paint has good hiding potential, i.e., it can cover or hide mostsurface imperfections. However, flat paint tends to attract dirt, soil,and other stain-forming materials. Without being bound to theory, it isbelieved that flat paint is more porous and, therefore, particulatematter, including dirt, soil particles, and other residues are easilytrapped within the paint surface.

Architectural surfaces coated with flat finish latex coatingcompositions or paints are difficult to clean, as dirt and soilparticles become trapped within the pores of the dried paint. Typically,using an alkali soluble support resin to make the coating compositionprovides slight improvement in stain resistance or washabilityproperties. However, these paints have poor scrub resistance and infact, stains are removed only as a result of the removal of one or morelayers of the paint itself. Surprisingly, and in contravention ofindustry bias, the coating composition described herein, when used in apaint composition, and especially a flat finish paint, for example,demonstrates exceptional stain resistance or washability.

In an embodiment, the coating composition or paint described hereinincludes a polymer system made by controlling the molecular weight andacid content of one or more polymers. The term “polymer system,” as usedherein refers to a mixture, blend or other combination of one or morelatex polymers. The latex polymers included in the polymer system may behomopolymers, heteropolymers or copolymers, blends of one or moremonomers, one-component, two-component or multi-component blends ofpolymers, multistage latex polymers, combinations thereof and the like.

The polymer systems described herein preferably include one or morewater-dispersible polymers, or one or more latex polymers. Such polymersare well-known in the coating industry and include a wide variety ofpolymers.

In certain embodiments, suitable polymers include polyurethanes,epoxies, polyamides, chlorinated polyolefins, acrylics, oil-modifiedpolymers, polyesters, and mixtures or copolymers thereof, for example.Such polymers are readily synthesized using conventional techniquesknown to those of skill in the art.

Preferably, the one or more water-dispersible or latex polymers includeone or more polymerization product(s) of (i) ethylenically unsaturatedmonomers, such as, for example, alkyl and alkoxy (meth)acrylates, vinylesters of saturated carboxylic acids, monoolefins, conjugated dienes,polyfunctional acrylates, and the like, optionally with (ii) one or moremonomers, such as, for example, styrene, methyl methacrylate, butylacrylate, 2-ethylhexyl acrylate, vinyl acetate, acrylonitrile, vinylchloride, and the like.

Suitable ethylenically unsaturated monomers include, for example,acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propylacrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate,ethyl methacrylate, propyl methacrylate, butyl methacrylate,2-ethylhexyl methacrylate, hydroxyethyl acrylate, hydroxyethylmethacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, glycidylmethacrylate, 4-hydroxybutyl acrylate glycidyl ether,2-(acetoacetoxy)ethyl methacrylate (AAEM), diacetone acrylamide,acrylamide, methacrylamide, methylol (meth)acrylamide, styrene, α-methylstyrene, vinyl toluene, vinyl acetate, vinyl propionate, allylmethacrylate, and mixtures thereof. Preferred monomers include styrene,methyl methacrylate, methacrylic acid, acetoacetoxy ethyl methacrylate,butyl acrylate, and the like.

Suitable polyfunctional acrylates include, for example, di-, tri- andtetra-functional acrylates such as dipropylene glycol diacrylate(DPGDA), propoxylated glyceryl triacrylate (GPTA), pentaerythritoltetraacrylate, dipentaerythritol tetraacrylate, mixtures thereof, andthe like. Preferred polyfunctional acrylate monomers includepentaerythritol tetraacrylate, dipentaerytrithol tetraacrylate, and thelike.

The latex polymer may also be stabilized with an alkali-soluble polymer.Alkali-soluble polymers may be prepared by making a polymer with acrylicor methacrylic acid or other polymerizable acid monomer (usually greaterthan 10%) and solubilizing the polymer by addition of ammonia or otherbase. Examples of suitable alkali-soluble support polymers are JONCRYL675 and JONCRYL 678, and the like.

The polymer system described herein may be a one-component system, atwo-component system, or a multi-component system. In an embodiment, thepolymer system described herein is a one-component system that includesone or more latex polymers, wherein the latex polymers may behomopolymers, copolymers or blends of one or more monomers, includingethylenically unsaturated monomers as described above.

Various methods can be used to prepare the polymer system describedherein, including by conventional methods known to those of skill in theart. By controlling the type and amount of monomers selected, i.e. bycontrolling the acid content and molecular weight of the monomersselected, a polymer system suitable for low VOC coating compositions orpaints may be formed, and the polymer system preferably providesexcellent performance characteristics, such as, for example, scrubresistance and washability or stain resistance, especially when thesystem is used in a flat finish paint.

In certain embodiments, the polymer system described herein may beprepared in a one-pot synthesis, wherein one or more monomers aresequentially fed into a single reaction vessel to obtain a polymersystem with the desired characteristics. In other embodiments, a polymerblend is prepared by mixing two or more polymers together to obtain apolymer system as described herein.

In an embodiment, the present invention includes a method to make acoating composition or paint composition. The method includes the stepsof providing one or more latex polymers and adjusting the acid contentand molecular weight of the one or more latex polymers to obtain apolymer system having at least about 10% to 30%, preferably 15% to 25%of the system includes polymers having molecular weight of about 10,000to about 40,000, preferably 15,000 to 35,000, more preferably 20,000 to30,000, and acid percent of about 2 to 20, preferably 5 to 10.

In an aspect, the polymer system may be made by combining a firstpolymer with a second polymer, such that the ratio of the first polymerto the second polymer is 0:100 to 100:0, preferably 10:90 to 90:10, morepreferably 30:70 to 70:30, most preferably 50:50. In another aspect, thepolymer system may be made by combining a first polymer comprising about40 to 95 wt %, preferably 45 to 90 wt %, more preferably 50 to 85 wt %,of the total weight of the polymer system, with a second polymercomprising about 5 to 60 wt %, preferably 10 to 55 wt %, more preferably15 to 50 wt % of the total weight of the polymer system. In yet anotheraspect, either the first or second polymer may be an alkali-solublesupport polymer.

In a preferred embodiment, irrespective of the preparative or syntheticmethod used, the type and/or concentration of the monomer or polymerreactants are varied to produce a polymer system where a specificproportion of the system has a specific molecular weight and specificacid percent or theoretical acid number. In a preferred aspect, thepolymer system described herein includes one or more latex polymers,wherein at least about 10% to 30%, preferably 15% to 25% of the systemincludes polymers having molecular weight of about 10,000 to about40,000, preferably 15,000 to 35,000, more preferably 20,000 to 30,000,and acid percent of about 2 to 10, preferably 5 to 7. In a preferredaspect, the polymer system described herein includes one or more latexpolymers, wherein at least about 10% to 30%, preferably 15% to 25% ofthe system includes polymers having molecular weight of about 10,000 toabout 40,000, preferably 15,000 to 35,000, more preferably 20,000 to30,000, and theoretical acid value of about 25 to 70, preferably 30 to65.

In an embodiment, the coating composition or paints made with thepolymer system described herein demonstrate excellent washability orstain resistance. Washability is measured by a standard test asdescribed below, and washability ratings are assigned on a scale from 0to 10, where a rating of 0 corresponds to very poor stain removal, and arating of 10 corresponds to complete stain removal. In an aspect, thepaints described herein show washability ratings over either 25 cyclesor 100 cycles of testing of preferably at least 6, more preferably atleast 7, and most preferably at least 8.

The composition described herein may include other components oradditives, added to either the reaction mixture of monomers used to makethe composition, to the polymer system, or to a paint composition thatincludes the polymer system described herein. Methods of making paintsare known to those of skill in the art. Suitable additives used in paintcompositions are known to those of skill in the art and include, forexample, coalescent agents, pigments, surfactants, open time agents, pHadjustors, initiator and chaser solutions, cross-linking agents,preservatives, defoaming agents, anticorrosive agents, and combinationsthereof.

In an aspect, the coating composition described herein may include acoalescing agent that aids in film formation. Preferred coalescingagents have VOC content of less than about 50%, preferably less thanabout 30%, more preferably, less than about 20%, and most preferably,less than about 15%. Exemplary suitable coalescing agents include lowVOC compounds of the type described in detail at least in U.S. Pat. Nos.6,762,230 and 7,812,079. Other suitable low VOC coalescents includeOptifilm (Eastman Chemical, Kingsport Tenn.), Loxanol (Cognis, KankakeeIll., now BASF), Archer RC (ADM, Decator Ill.), and the like.Conventional coalescing agents such as, Texanol (Eastman Chemical) andthe like can also be used, either alone or in combination with othersolvents such as, for example, 2-butoxyethanol (butyl cellosolve),diethylene glycol monobutyl ether (butyl carbitol), and the like,provided low VOC levels are maintained in the coating composition orpaint.

In an aspect, the coating composition, when included in a paint, forexample, may include one or more pigments, including pigments or fillersused to tone or opacify the paint. Suitable examples of pigmentsinclude, without limitation, titanium dioxide white, carbon black, lampblack, black iron oxide, red iron oxide, yellow iron oxide, brown ironoxide (a blend of yellow and red oxide with black oxide), phthalocyaninegreen, phthalocyanine blue, organic reds (such as naphthol red,quinacridone red and toluidine red), quinacridone magenta, quinacridoneviolent, DNA orange, and/or organic yellows (such as Hansa yellow), forexample.

In an aspect, the coating composition described herein can be used in apaint that further includes one or more additives. Suitable additivesinclude, without limitation, fillers, thixotropes, rheologicalmodifiers, matting agents, and the like. The additives may include oneor more ingredients added to a paint to modify the properties or enhancepaint performance during storage, handling, application and other orsubsequent stages. Desirable performance characteristics of a paintinclude, for example, chemical resistance, abrasion or scrub resistance,tack resistance, hardness, gloss, reflectivity, appearance and/or acombination of such properties and similar other properties. Preferredperformance enhancing additives include lacquers, waxes, flattingagents, additives to prevent mar, abrasion and the like.

The invention is illustrated by the following examples. It is to beunderstood that the particular examples, materials, amounts, andprocedures are to be interpreted broadly in accordance with the scopeand spirit of the inventions as set forth herein. Unless otherwiseindicated, all parts and percentages are by weight and all molecularweights are weight average molecular weight. Unless otherwise specified,all chemicals used are commercially available from, for example,Sigma-Aldrich, St. Louis, Mo.

EXAMPLES

Unless indicated otherwise, the following test methods were utilized inthe Example(s) that follow(s).

Stain Resistance or Washability

The stain resistance or washability of the paint is tested using ASTMD3450-00 (Standard Test Method for Washability Properties of InteriorArchitectural Coatings).

Example 1

To a 3-liter cylindrical flask was charged 1250 g deionized water and2.0 g Rhodapon UB (Rhodia). The flask was fitted with an agitator andflask head, and then placed in a water bath heated to 80° C. A monomeremulsion was made by first adding 300 g deionized water and 8.0 gRhodapon UB to a beaker and agitating. Each of the following was thenadded: 234 g butyl acrylate, 297 g methyl methacrylate, 60 g methacrylicacid, and 9.0 g dodecanethiol.

60 g of the monomer emulsion was added to the flask and allowed toequilibrate. When the flask reached 78° C., 1.8 g ammonium persulfate in30 g deionized water was added to the flask and allowed to react for 15minutes before starting feed of the remaining monomer emulsion into theflask over a 90 minute time period. The flask was held at 80° C. for 30minutes following completion of the monomer feed, and was then allowedto cool. At 55° C., a mixture of 39 g ammonium hydroxide (26%) in 60 gdeionized water was fed to the flask over a 20 minute time period. Lineswere then rinsed with 85 g deionized water and allowed to cool to 35° C.before decanting. The resulting latex had a solids content (NVM) of25.3% and a pH of 8.7.

Example 2

To a 3-liter cylindrical flask was charged 600 g deionized water and 1.0g Rhodapon UB (Rhodia). The flask was fitted with an agitator and flaskhead, and then placed in a water bath heated to 80° C. A monomeremulsion was made by first adding 350 g deionized water and 50.0 gRhodapon UB to a beaker and agitating. Each of the following was thenadded: 612 g butyl acrylate, 560 g methyl methacrylate, and 18 gmethacrylic acid.

60 g of the monomer emulsion was added to the flask and allowed toequilibrate. When flask reached 78° C., 1.8 g ammonium persulfate in 30g deionized water was added to the flask and allowed to react for 15minutes before starting feed of the remaining monomer emulsion into theflask over a 3-hour time period. The flask was held at 80° C. for 30minutes following completion of the monomer emulsion feed, and was thenallowed to cool. At 40° C., 7 g of ammonium hydroxide (26%) was added tothe flask, and lines were rinsed with 54 g deionized water. The flaskwas allowed to cool to 35° C. before decanting. The resulting latex hadsolids content (NVM) of 49.9% and a pH of 8.9.

Example 3

To a 3-liter cylindrical flask was charged 750 g deionized water and 1.6g Rhodapon UB (Rhodia). The flask was fitted with an agitator and flaskhead and placed in a water bath heated to 80° C. A monomer emulsion wasmade by first adding 120 g deionized water and 2.6 g Rhodapon UB to abeaker and agitating. Each of the following was then added: 30 g butylacrylate, 155 g methyl methacrylate, 20 g methacrylic acid, and 3.3 gdodecanethiol.

A second monomer emulsion was made by first adding 190 g deionized waterand 40 g Rhodapon UB to a beaker and agitating. Each of the followingwas then added: 515 g butyl acrylate, 462 g methyl methacrylate, and 16g methacrylic acid.

30 g of the first monomer emulsion was added to the flask and allowed toequilibrate. When the flask reached 78° C., 1.8 g ammonium persulfate in30 g deionized water was added to the flask and allowed to react for 15minutes before starting feed of the first monomer emulsion into theflask over a 30 minute time period. The flask was held at 80° C. for 10minutes following completion of the monomer emulsion feed, and then amixture of 14 g ammonium hydroxide in 55 g deionized water was added tothe flask over a 10 minute time period. Next, 1.8 g ammonium persulfatein 20 g deionized water was added to the flask and a feed of the secondmonomer emulsion into the flask was started over a 2-hour time period.The flask was held at 80° C. for 30 minutes following the completion ofthe second monomer emulsion feed, and then allowed to cool to 40° C. 5.0g ammonium hydroxide were added to the flask and lines were rinsed with143 g deionized water and allowed to cool to 35° C. before decanting.The resulting latex had a solids content (NVM) of 45.5% and a pH of 7.6.

Example 4

Coating compositions #1 to #7 were prepared by blending 10% of a polymermade according to Example 1 and 90% of a polymer made according toExample 2. The acid content and molecular weight of the first polymerwas adjusted as shown in Table 1. The coating compositions were includedin paints made by conventional methods known to those of skill in theart. As demonstrated in Table 1, acid content and molecular weightcontribute to stain resistance, and is further confirmed by statisticalanalysis (MW p value=0.036; acid content p value=0.105), whereas Tg doesnot have a statistical significant or predictable effect on thewashability of the tested compositions.

TABLE 1 Washability % Acid # Stain Mw PDI Acid Tg (Theo) removal 120,405 3.85 10 65° C. 65.1 6.1 2 21,720 13.13 5 62° C. 32.5 5.1 3 25,0355.19 5 20° C. 32.5 4.4 4 24,355 4.91 10 22° C. 65.1 5.5 5 52,940 6.57 1020° C. 65.1 5.4 6 47,970 6.53 5 18° C. 32.5 4 7 59,505 16.68 5 65° C.32.5 3.6

The complete disclosure of all patents, patent applications, andpublications, and electronically available material cited herein areincorporated by reference. The foregoing detailed description andexamples have been given for clarity of understanding only. Nounnecessary limitations are to be understood therefrom. The invention isnot limited to the exact details shown and described, for variationsobvious to one skilled in the art will be included within the inventiondefined by the claims. The invention illustratively disclosed hereinsuitably may be practiced, in some embodiments, in the absence of anyelement which is not specifically disclosed herein.

What is claimed is:
 1. A coating composition, comprising: a polymersystem comprising one or more latex polymers, wherein at least about 10%up to 30% by weight of the polymer system includes at least one polymerhaving a molecular weight of about 10,000 to about 40,000 and an acidpercent of about 5 to 10, wherein the coating composition has a pigmentvolume concentration (PVC) of about 30 to
 55. 2. The coating compositionof claim 1, wherein the one or more latex polymers include one or morepolymerization products of one or more ethylenically unsaturatedmonomers.
 3. The coating composition of claim 1, wherein the one or morelatex polymers include one or more polymerization products of one ormore ethylenically unsaturated monomers selected from the groupconsisting of acrylic acid, C₁-C₈ esters of acrylic acid, substitutedC₁-C₈ esters of acrylic acid, methacrylic acid, C₁-C₈ ester ofmethacrylic acid, substituted C₁-C₈ esters of methacrylic acid, styrene,a-methyl styrene, vinyl toluene, vinyl acetate, vinyl propionate, allylmethacrylate, and mixtures thereof.
 4. The coating composition of claim1, wherein the one or more latex polymers include one or morepolymerization products of one or more acrylic monomers.
 5. The coatingcomposition of claim 1, wherein the one or more latex polymers compriseone or more alkali-soluble support polymers.
 6. The coating compositionof claim 1, wherein the polymer system comprises: a first latex polymercomprising about 50 to 85 wt % of the polymer system, based on the totalweight of the system; and a second latex polymer comprising about 15 to50 wt % of the polymer system, based on the total weight of the system.7. The coating composition of claim 1, wherein the polymer systemcomprises a first latex polymer and a second latex polymer, wherein theratio of the first latex polymer to the second latex polymer is from10:90 to 90:10.
 8. The coating composition of claim 1, wherein the atleast one polymer being at least about 10% up to 30% by weight of thepolymer system has a molecular weight of about 20,000 to 30,000.
 9. Thecoating composition of claim 1, wherein the at least one polymer beingat least about 10% up to 30% by weight of the polymer system has amolecular weight of about 15,000 to about 25,000.
 10. The coatingcomposition of claim 1, wherein the at least one polymer being at leastabout 10% up to 30% by weight of the polymer system has a theoreticalacid value of about 25 to about
 75. 11. The coating composition of claim1, wherein the at least one polymer being at least about 10% up to 30%by weight of the polymer system has a theoretical acid value of about 30to about
 70. 12. The coating composition of claim 1, wherein thecomposition exhibits a washability rating of at least
 8. 13. The coatingcomposition of claim 1, wherein the polymer system comprises apolymerization product from styrene, butyl acrylate,2-(acetoacetoxy)ethyl methacrylate, methyl methacrylate, and butylmethacrylate.
 14. The coating composition of claim 1, wherein thepolymer system comprises at least one copolymer derived from styrene,butyl acrylate, 2-(acetoacetoxy)ethyl methacrylate, methyl methacrylate,and butyl methacrylate.
 15. The coating composition of claim 1, whereinthe coating composition exhibits a washability rating of at least
 6. 16.The coating composition of claim 1, wherein the coating compositionexhibits a washability rating of at least
 7. 17. The coating compositionof claim 1, wherein at least about 15% up to 30% by weight of thepolymer system includes the at least one polymer.
 18. The coatingcomposition of claim 1, wherein at least about 15% up to 25% by weightof the polymer system includes the at least one polymer.
 19. The coatingcomposition of claim 1, wherein the at least one polymer having themolecular weight of about 10,000 to about 40,000 and the acid percent ofabout 5 to 10 is methacrylic acid.